Question

find the sum of numbers in an AR
1 + 3 + 5 + 7.......149​

Answer 1

S=5625

explain

a =1,d =2

an= a + (n-1)d

an = 1 + 2n -2

149 = -1+2n

150/2 =n

n = 75

s = 75/2(2+74×2)

s= 75/2 ×150

s = 5625